Fungicides



United States Patent O 3,081,222 FUNGICIDES Howard A. Hageman,Southbury, and John A. Riddell, Hamden, Conn., assignors to UnitedStates Rubber Company, New York, N.Y., a corporation of New Jersey NoDrawing. Filed Mar. 11, 1960, Ser. No. 14,211

13 Claims. (Cl. 167-333) wherein R stands for an aromatic orcycloaliphatic radi- V cal and R stands for hydrogen and R stands forhydro gen or methyl, or wherein R and R each stand for the same alkylradical having one to four carbon atoms, and R stands for hydrogen ormethyl. The Z-aminoimidazolines are strong bases which form watersoluble salts with acids such as hydrochloric, hydrobromic, sulfuric,nitric, acetic and carbonic acids. They may be used as fungicides in theform of the free base or as such salts. The Z-aminoimidazolines of thepresent invention are prepared in known manner by treating a2-alkylthioimidazoline or a salt thereof with an amine which replacesthe 2-a1kylthio group according to the following reaction:

The procedure is essentially that of Kranzlein and Ochwat, US. PatentNo. 1,912,849 who prepared several 2- aminoimidazolines for use asvulcanization accelerators and dyestuff intermediates.

In the-preparation of the present Z-aminoimidazolines, the syntheticprocedure consists in heating Z-n-butylthioimidazoline hydrobromide orthe 4-alkyl-2-n-butylthioimidazoline hydrobromide with the appropriateprimary or secondary amine in a medium of n-amyl alcohol, caus-.

ing the evolution of butyl mercaptan and the formation of thehydrobromide of the resulting Z-aminoimidazoline. Where desired toliberate the free base, the hydrobromide salt was treated with strongalkali. When these compounds are applied as fungicides, it is immaterialwhether they are in the form of the free bases or the salts thereof.

The following illustrates the preparation of the chemicals of thepresent invention. The particular Z-p-anilinophenylaminoimidazolineformed in a new chemical. The various other Z-aminoimidazolinesaccording to the present invention are prepared in a similar manner.

Preparation of Z-p-AnilinophenyIaminoimidazoline In a 500 ml. flask wasplaced a mixture of 70 g. ofv

p-aminodiphenylamine, 86 g. of Z-n-butylthioimidazoline hydrobromide and200 ml. of n-amyl alcohol. With a heating period the temperature of theboiling mixture I 313M222 Patented Mar. 12, 1963 gradually rose from aninitial temperature of -135 C. to a final temperature of -165 C. Afterallowing the reaction mixture to cool to 8590 C. it was treated with 200ml. of isopropanol and then allowed to stand overnight.

The blue-gray, crystalline solid which had precipitated was collected byfiltration and the filter cake was washed with several portions ofether. Upon recrystallizing this product from methanol there wasobtained the hydrobromide of 2-p-anilinophenylaminoimidazoline wassparking blue-gray needles melting at 212-213 C.

Calculated for C H N Br: Percent N=16.8; Percent Br=24.0. Found: PercentN=l6.0; percent Br=22.8.

By treating this hydrobrornide with sodium hydroxide in a medium ofmethanol and then diluting this solution with water, the free base of2-p-anilinophenylaminoimidazoline is obtained as a light tan powderwhich melts at 180-182" C.

The chemicals of the present invention may be applied ice to plants,which term includes various plant parts such as seeds, flowers, fruits,vegetables and foliage, as a liquid or spray in a liquid carrier such asan organic solvent or water, or may be applied as a dust in admixturewith a powdered solid carrier such as the various mineral silicates,e.g. mica, talc, pyrophillite, and clays. The chemicals of the inventionmay be applied in admixture with surface-active agents which may beanionic, non-ionic or cationic surface-active agents, and which act aswetting agents for the chemicals. Such surface-active agents are wellknown and reference is made to U.S. Patent No. 2,547,724, columns 3 and4 for detailed examples of the same. The chemicals of the invention maybe admixed with powdered solid carriers, such as mineral silicates,together with a surface-active agent so that a wettable powder may beobtained which may be applied directly to plants, or which may be shakenup with water for application to the plants in that form. Suchapplications of the chemicals may be made to disease-free plants forprotective purposes, and also to fungus-infected plants.

The effectiveness of the chemicals of the present invention asfungicides is demonstrated by testing their ability to control thedamaging effects of the fungus Uromyces phaseoli var. typica Arth. onPinto beans. The disease caused by this fungus is commonly known as beanrust. As wiil be more fully apparent in the description of the testprocedure below, the chemical compounds of the present inventionfunction as systemic fungicides. It is to beemphasized that the numberof chemical compounds which exhibit systemic fungicidal activity againstbean rust is considerably smaller than those which are active asprotective fungicides. There are many distinct advantages of a systemicfungicide over a protective fungicide. A protective fungicide iseffective only as long as the chemical is retained by the plant. Inpractice, this is usually a relatively short period because of itssusceptibility to wash off and Weathering. Further, the protectivefungicide only prevents the spread of certain diseases and cannotusually eradicate the disease if it is already well established. Thereare many serious diseases such as Wilts and soil-borne diseases which,because of their systemic nature or because infection occurs through theroot, protective fungicides cannot control. A systemic fungicide, whichis absorbed by the plant and translocated to all parts of the plant andis active at all these various sights, overcomes the disadvantages of aprotective fungicide. A systemic fungicide does not only have thepotential of protecting against any disease for a comparatively longtime but may also eradicate any disease organisms established in theplant tissue. Thus a single chemical application will afford a long andcontinual protection against disease. It is of course 3 essential thatthe systemic fungicide is not phytotoxic and does not kill the plant.Higher alkyl substituents, ie an alkyl substituent having eight or morecarbon atoms, in the 2-alkylaminoimidazolines impart a high degree ofphytotoxicity to the compounds and hence such compounds are of no use inthe present invention.

The following procedure was used to test various chemicals of thepresent invention as systemic fungicides.

Urediospores or summer spores of Uromyces phaseoli var. typica Arth. arecollected from previously inoculated plants by brushing the spores intoa vial. A suspension of 35 mg. of spores in a liter of water is sprayedto runoff on the expanding primary leaves of ten-day old Pinto beanplants. The infected plants are placed in a continual mist humiditychamber at 75 F. for 24 hours, then in the greenhouse for an additional24 hours. At this time the organisms are established within the planttissues and are not affected by the usual protective fungicides.

One gram of each of the chemicals to be tested is ground with three ml.of acetone and 50 mg. of a nonionic surface-active agent (a condensationproduct of an alkyl phenol and ethylene oxide). The acetone andsurface-active agent are known to be inactive in this biological test.The above mixtures are diluted with sufficient water to make solutionscontaining 2000 parts per million (p.p.m.) of each of the chemicalsbeing tested. Each of these solutions is sprayed to run-off on three ofthe infected bean plants described above. These plants are heldovernight at 70 to 75 F. and 95-100% relative humidity, then allowed todry in the shade before being placed in the greenhouse. In 8 to 10 daysthe sori or brown pustules appear on the upper and lower leaf surfacesof untreated plants. The number of pustules on the treated plants is anindex of the activity of the chemical being tested. Such data, expressedas percent control, are shown in the following table:

Chemical- Percent control 2-anilinoimidazoline (as free base) 97 2anilino 4 methylimidazoline (as hydrobromide) 982-p-tolylaminoimidazoline (as free base) 1002-m-chloroanilinoimidazoline (as free base)--- 100 2 panilinophenylaminoimidazoline (as free base) 982-p-anilinophenylaminoimidazoline (as hydrobromide) 100 2cyclohexylaminoimidazoline (as hydrobromide) 982-di-n-butylaminoimidazoline (as free base)"- 99 None of the plantstreated with the chemicals in the table above showed any evidence ofphytotoxicity. On the other hand the same treatment with 2-n-octylaminoimidazoline killed the plants, showing that higher alkyl substituentsrender the 2-alkylaminoimidazolines phytotoxic and of no value in thefungicidal treatment of plants.

It is clear that the Z-aminoimidazolines exemplified in the above tableare active systemically. These chemicals are absorbed by the plant andtransported to the diseased cells. This absorption by and translocationwithin the plant has been substantiated by tests in which only part ofthe infected plant is treated with the chemical; control of the diseaseextends to untreated portions of the plant.

This application is a continuation-in-part of our application Serial No.813,055, filed May 14, 1959, now abandoned.

Having thus described our invention, what we claim and desire to protectby Letters Patent is:

1. A fungicidal composition comprising a chemical having the generalformula wherein R stands for a member selected from the group consistingof phenyl, tolyl, chlorophenyl, anilinophenyl and cyclohexyl radicalswhen R is hydrogen, and R stands for an alkyl radical having 1 to 4carbon atoms when R is the same alkyl radical having 1 to 4 carbon atomsas R and wherein R stands for a member selected from the groupconsisting of hydrogen and methyl, said composition containing asurface-active wetting agent.

2. A fungicidal composition comprising Z-p-anilinophenylaminoimidazolineand a surface-active wetting agent.

3. A fungicidal composition comprising Z-cyclohexylaminoimidazoline anda surface-active wetting agent.

4-. A fungicidal composition comprising Z-di-n-butylaminoimidazoline anda surface-active wetting agent.

5. A fungicidal composition comprising Z-anilinoimidazoline and asurface-active wetting agent.

6. A fungicidal composition comprising a 2-p-tolylaminoimidazoline and asurface-active wetting agent.

7. The method of controlling fungi on plants which comprises applying toplants a chemical having the general formula R1 O--N CHz-NH \R:

wherein R stands for a member selected from the group consisting ofphenyl, tolyl, chlorophenyl, anilinophenyl and cyclohexyl radicals whenR is hydrogen, and R stands for an alkyl radical having 1 to 4 carbonatoms when R is the same alkyl radical having 1 to 4 carbon atoms as Rand wherein R stands for a member selected from the group consisting ofhydrogen and methyl.

8. The method of controlling fungi on plants which comprises applyingZ-p-anilinophenylaminoimidazoline to plants.

9. The method of controlling fungi on plants which cinnprises applying2-cyclohexylarninoimidazoline to p ants.

10. The method of controlling fungi on plants which comprises applying2-di-n-butylaminoimidazoline to plants.

11. The method of controlling fungi on plants which comprises applying2-anilinoimidazoline to plants.

12. The method of controlling fungi on plants which comprises applying2-p-tolylaminoimidazoline to plants.

13. The method which comprises treating fungus infected plants with achemical having the general formula wherein R stands for a memberselected from the group consisting of phenyl, tolyl, chlorophenyl,anilinophenyl and cyclohexyl radicals when R is hydrogen, and R standsfor an alkyl radical having 1 to 4 carbon atoms when R is the same alkylradical having 1 to 4 carbon atoms as R and wherein R stands for amember selected from the group consisting of hydrogen and methyl.

References Cited in the file of this patent UNITED STATES PATENTS1,860,036 Kranzlein et al. May 24, 1932 1,912,849 Kranzlein et al June6, 1933 2,213,474 Puetzer Sept. 3, 1940 2,415,047 Senkus Ian. 28, 19472,540,170 Law et al. Feb. 6, 1951 2,586,844 McKay Feb. 26, 19522,689,249 Benneville etal Sept. 14, 1954 2,988,478 Gordon June 13, 1961

1. A FUGICIDAL COMPOSITION COMPRISING A CHEMICAL HAVING THE GENERALFORMULA